Dog Collar with LED Lights, Multi-Function, Size Medium buckle closure IMPROVED DOG VISIBILITY & SAFETY - the latest Ultra-Bright LED's provide optimal dog visibility during the dark winter months, reducing the risk of potential collisions & improving dog safety because your dog can be seen at distance by other dog walkers, joggers, runners, cyclists, motorists, etc, Four modes: slow blinking, fast blinking, sustained lighting, and off INNOVATIVE DESIGN & PREMIUM QUALITY - fully adjustable, easy to put on & use, comfy, one click mode selection - always on, rapid flash, slow flash and off, with a quick-release POM buckle, an enclosed battery case & switch for added protection & a better look, & super-strong 100% nylon webbing with high-tensile stitching for maximum strength & dog security. WEATHERPROOF - good for all weather conditions, the LED GLOW collar is water-repellent, it has rust-proof components, & it is lightweight, strong, durable & built to last with only the best top quality materials & components. weather resistant, shock-resistant. Provides visibility up to 1,000 Feet in the dark, The LED Dog Safety collar provide maximum visibility & ULTIMATE SAFETY for YOU & YOUR DOG on dark evenings, dusk, dawn, mornings & at night. , How to measure your dog's neck size: measure around the neck close to the shoulder and allow room for a comfortable fit. Buckle closure